Near-infrared absorbing material fine particle dispersion, near-infrared absorber, near-infrared absorber laminate, and laminated structure for near-infrared absorption

Abstract

A near-infrared absorbing material fine particle dispersion, a near-infrared absorber laminate, and a laminated structure for near-infrared absorption can exhibit higher near-infrared absorption property, compared to near-infrared fine particle dispersions, near-infrared absorber laminates, and laminated structures for near-infrared absorption, containing tungsten oxides or composite tungsten oxides according to the conventional art. Also, a near-infrared absorbing material fine particle dispersion in which composite tungsten oxide fine particles, each particle containing a hexagonal crystal structure, and a polymer compound with maleic anhydride introduced therein are contained in the polypropylene resin, and the near-infrared absorber laminate and the laminated structure for near-infrared absorption using the dispersion.

The invention claimed is: 
     
       1. A near-infrared absorbing material fine particle dispersion, comprising;
 composite tungsten oxide fine particles, and 
 modified polyolefin modified with one or more kinds selected from maleic anhydride and carboxylic anhydride, in polypropylene resin, wherein 
 the composite tungsten oxide fine particles are represented by a general formula MxWyOz in which M is one or more elements selected from Cs and Rb, W is tungsten, O is oxygen, and x, y, and z satisfy 0.20≤x/y≤0.37 and 2.2≤z/y≤3.0, 
 the composite tungsten oxide fine particles have a hexagonal crystal structure, 
 a crystallite size of the composite tungsten oxide fine particles is 10 nm or more and 70 nm or less, 
 a crystallite of the composite tungsten oxide fine particles is a single crystal, 
 an amorphous phase volume ratio is 50% or less in the composite tungsten oxide fine particles, 
 the amorphous phase exists on an outer periphery of each of the composite tungsten oxide fine particles, 
 a dispersed particle size of the composite tungsten oxide fine particles is 10 nm or more and 200 nm or less, 
 an addition amount of the modified polyolefin is 1 part by mass or more and 2,000 parts by mass or less with respect to 100 parts by mass of the near-infrared absorbing material fine particles, 
 the near-infrared absorbing material fine particle dispersion has transparency in a visible light region, and 
 a haze value of the near-infrared absorbing material fine particle dispersion is 10% or less at visible light transmittance of 85% or less. 
 
     
     
       2. The near-infrared absorbing material fine particle dispersion according to  claim 1 ,
 wherein a weight average molecular weight of the modified polyolefin is 1,000 or more and 100,000 or less. 
 
     
     
       3. The near-infrared absorbing material fine particle dispersion according to  claim 1 ,
 wherein an acid number of the modified polyolefin is 1 mgKOH/mg or more and 150 mgKOH/mg or less. 
 
     
     
       4. The near-infrared absorbing material fine particle dispersion according to  claim 1 ,
 wherein a surface of the composite tungsten oxide fine particles is coated with an oxide containing one or more elements selected from Si, Ti, Zr, and Al. 
 
     
     
       5. A near-infrared absorber,
 wherein the near-infrared absorbing material fine particle dispersion according to  claim 1  is diluted and melt-kneaded with polypropylene resin or a heterogeneous thermoplastic resin having compatibility with the polypropylene resin, and molded into any one shape selected from a plate, a film, and a thin film. 
 
     
     
       6. A near-infrared absorber laminate, comprising the near-infrared absorber according to  claim 5  laminated on a base material. 
     
     
       7. A laminated structure for near-infrared absorption,
 wherein the near-infrared absorber laminate according to  claim 6  is opposed to a laminated plate selected from sheet glass, a plastic plate, and a plastic plate containing fine particles having a near-infrared absorption function, or is present between two or more laminated plates selected from the sheet glass, the plastic plate, and the plastic plate containing fine particles having the near-infrared absorption function. 
 
     
     
       8. A laminated structure for near-infrared absorption, comprising the near-infrared absorber according to  claim 5  present between two or more laminated plates selected from sheet glass, a plastic plate, and a plastic plate containing fine particles having a near-infrared absorption function. 
     
     
       9. The near-infrared absorbing material fine particle dispersion according to  claim 1 ,
 wherein the crystallite size of the composite tungsten oxide fine particles is 25 nm. 
 
     
     
       10. The near-infrared absorbing material fine particle dispersion according to  claim 1 ,
 wherein the dispersed particle size of the composite tungsten oxide fine particles is 92.2 nm or more and 132.2 nm or less. 
 
     
     
       11. The near-infrared absorbing material fine particle dispersion according to  claim 1 ,
 wherein the addition amount of the modified polyolefin is 40 parts by mass or more and 1,000 parts by mass or less with respect to 100 parts by mass of the near-infrared absorbing material fine particles.